Performers at public music concerts typically use powerful amplification systems which output very high noise levels. This can cause damage to the hearing of members of the audience as well as to sound technicians and other personnel who regularly attend such concerts in a working capacity. Hearing damage can include loss of sensitivity at certain frequencies, or generally across the whole sound audio frequency spectrum (20 Hz to 20,000 Hz), or can cause hearing disabilities such as tinnitus. Often such damage is not appreciated by the victim at the time and further damage will occur because the victim will listen subsequently to audio signals at increased volume to compensate for the hearing loss already suffered. Damage is particularly acute in the higher frequency part of the audible range and such higher frequencies are very common at rock music concerts.
There is therefore a need for methods and devices which can control the audio dosage output of public broadcast systems used at concerts, and of other audio output systems.